Modelling grooves on a cylinder
You may do it fast using the Array Modifier and some basic modeling tools.


Add a cylinder with no fill, then subdivide it in the middle with Ctrl+R. Bevel the loopcut with Ctrl+B and set its thickness. Next inset the faces with I to create extra loopcuts for subsurf creasing. Then extrude the loop of faces (E) and scale it along Z and Y axis only (S,Shift+X). Repeat it twice, then inset the faces again. Finally add a Subsurf Modifier and apply the smooth shading. One segment is ready.


Add the Array Modifier and set it above the Subsurf. Set the Count number as you like and check the Merge checkbox.


To change the angle of the carvings select one in Edit Mode with B, then press Shift+Ctrl+Alt+S to shear it.


Finally you may apply the Array, add the Solidify Modifier (to give the pipe a thickness) and add loopcuts (Ctrl+R) at the edges of a pipe.